The ever more precise personalization of ophthalmic lenses of a frame intended to equip an individual to correct his vision requires increased knowledge of the visual behaviour of the individual under natural conditions of vision which are representative of the actual use of the said ophthalmic lenses.
Determining parameters of the visual behaviour of the individual then allows the optical design of the ophthalmic lenses that will be mounted in the frame to be improved.
In particular, during the optical design of progressive ophthalmic lenses, it is particularly important to have at one's disposal relevant optical design data in order to adequately reflect the use of these lenses in near vision and the posture adopted by the individual, in particular in a reading situation.
However, the measurements currently carried out by the optician on the individual are most often performed after the measurements performed with respect to adjustment of the frame. These measurements are therefore constrained and relate to one given frame, and hence they are not in practice reusable with another frame.
In addition, the frame may influence the visual behaviour or posture of the individual so that the measurements are taken under conditions in which the individual is not in his natural posture.
It is therefore often difficult to determine parameters of the visual behaviour of the individual under natural conditions.
As a result of this, the optical design of ophthalmic lenses on the basis of these visual-postural parameters is not optimal and hence the individual may experience discomfort when using such ophthalmic lenses. This is in particular true for progressive ophthalmic lenses, the optical design of which must be realized with care in order to ensure an optimal fit to the individual.